1. Field of the Invention
The present invention relates to a solid-state image capturing device having a color filter provided above each light receiving section provided on a surface of a semiconductor substrate, and configured with semiconductor elements for performing photoelectric conversion on image light from a subject to capture the image light; a manufacturing method for the solid-state image capturing device; a color filter; a forming method for the color filter; a liquid crystal display apparatus using the color filter; and an electronic information device, such as a digital camera (e.g., digital video camera and digital still camera), an image input camera, a scanner, a facsimile machine and a camera-equipped cell phone device, having the solid-state image capturing device, which is manufactured by the manufacturing method of the solid-state image capturing device, as an image input device in an image capturing section of the electronic information device, or an electronic information device having the liquid crystal display apparatus as a display section.
2. Description of the Related Art
Conventionally, it is known that a solid-state image capturing device capable of capturing a color image has a structure where color filters for optically separating incident light are provided above the respective corresponding light receiving sections provided on a surface of a semiconductor substrate.
A specific structure of a solid-state image capturing device having such color filters will be explained in detail with reference to FIG. 8.
FIG. 8 is a longitudinal cross sectional view showing an exemplary essential structure of a conventional solid-state image capturing device.
In FIG. 8, a conventional solid-state image capturing device 100 has a plurality of light receiving sections 102 for performing photoelectric conversion on incident light, formed in a matrix on a surface layer of a semiconductor substrate 101. On a semiconductor substrate 101, gate film 103 composed of polysilicon is formed adjacent to the light receiving section 102 so as to read out and transfer photoelectrically converted signal charges by each light receiving section 102. Further, on a substrate area other than each light receiving section 102, that is, on the gate film 103, for example, a shading film 104 is formed via interlayer insulation film, so that light will not enter. The shading film 104 is opened above each light receiving section 102. An interlayer insulation film 105a is formed on the semiconductor substrate 101, in which the light receiving sections 102 are formed, and the shading film 104 for the purpose of electric insulation.
Further, on the interlayer insulation film 105a, an interlayer insulation film 105b is formed on the interlayer insulation film 105a, so that the unevenness resulted from the shape of a base of the interlayer insulation film 105a is improved and color filters can be formed on the resultant flat surface. The interlayer insulation film 105b is composed of a transparent acrylic material and the like in order to improve adhesiveness to the color filters and improve optical transmittance.
On the interlayer insulation film 105b, a plurality of color filters 106a, 106b and 106c are arranged and formed in a corresponding manner to respective light receiving sections 102. Desirably, the color filters 106a, 106b and 106c are formed checkerwise in order as shown in FIG. 9, for example.
FIG. 9 is a plan view hypothetically showing a desirable formation of color filters shown together with light receiving sections 102. A-A′ in FIG. 9 corresponds to the left side of FIG. 8, and B-B′ in FIG. 9 corresponds to the right side of the FIG. 8.
On the color filters 106a, 106b and 106c, an interlayer insulation film 105c is formed for the purpose of protecting the color filters 106a, 106b and 106c and planarizing the base surface of microlenses 107 before forming the microlenses 107. On the interlayer insulation film 105c, microlenses 107 are formed in a corresponding manner to respective light receiving section 102 for the purpose of refracting incident light and condensing light that enters towards the shading film 104, which forms ineffective areas, into the light receiving section 102. Due to the microlenses 107, the amount of light that enters the light receiving sections 102 increases, improving the light receiving sensitivity.
Conventionally, the formation of the color filters 106a, 106b and 106c are performed as follows.
First, a photosensitive color filter material (material for the color filter 106a) is applied on the interlayer insulation film 105a up to a desired thickness by a spin coating method and the like. The applied color filter material is exposed by an exposing device so that a pattern will be left only in desired areas among areas corresponding to the positions of respective light receiving sections 102. A process using a developing solution is performed to pattern the color filter 106a. 
Next, a photosensitive color filter material (material for the color filter 106b) is applied on the interlayer insulation film 105a up to a desired thickness by a spin coating method and the like. The applied color filter material is exposed by an exposing device so that a pattern will be left only on another desired areas among areas corresponding to the positions of respective light receiving sections 102. A process using a developing solution is performed to pattern the color filter 106b. Similarly, a color filter 106c is further patterned on areas that remain after the formation of the color filters 106a and 106b among areas corresponding to the positions of respective light receiving sections 102.
A photosensitive material, including a pigment and a dye, is used as a color filter material, and desired color filters 106a, 106b and 106c are formed on desired light receiving sections 102 using a photolithography technique. The color filters 106a, 106b and 106c have a plurality of colors. In the case of FIG. 8, the color filters 106a, 106b and 106c are formed as a green color filter (G; green color), a blue color filter (B; blue color) and a red color filter (R; red color) respectively.
At this point, owing to the resolutions of the color filters 106a, 106b and 106c, corner portions (edge portion) of rectangular color filters 106a, 106b and 106c have blunt edges as shown in FIG. 10. Further, due to the alignment accuracy during the patterning, a gap (interval C) as shown in FIG. 10 or an overlapping portion D at the upper and lower end portions as shown in FIG. 8 is formed between adjacent color filters 106a, 106b and 106c. 
Reference 1, for example, proposes a method for forming a color filter that forms a color filter using a dye containing negative type curing composite that enables an excellent rectangular pattern formation. According to such a conventional method for forming a color filter, it is said that a color filter having an excellent rectangular pattern formation (accurate rectangle color filter having edges) can be formed with good cost-effectiveness.
Further, Reference 2, for example, proposes a method for forming a color filter, in which a newly developed photopolymerization initiator is mixed with a photosensitive colored composite for color filters. According to such a method for forming a color filter, it is said that the sensitivity of the photosensitive colored composite is significantly increased, so that sufficient curing with a small amount of exposure is possible, and further that an accurate pattern can be formed because the photosensitive colored composite has an excellent pattern forming capability.
Further, Reference 3, for example, proposes a method for forming a color filter, in which a color filter forming area in a base interlayer insulation film is processed in a concave form, and an edge portion of the color filter is formed into a thin film. According to such a method for forming a color filter, it is said that the color filter in a thin film form has an excellent pattern forming capability, so that an accurate pattern can be formed.
Further, Reference 4, for example, proposes a method for forming a color filter, in which a red alignment mark is formed concurrently with the formation of red color filters of all the color filters, and an alignment is performed with a red color alignment light by the red alignment mark to pattern a blue resist material concurrently with the formation of blue filters of all the color filters. According to such a method for forming a color filter, it is said that high contrast can be obtained at the formation of the blue filter due to the red alignment mark that does not absorb the red alignment light, so that the alignment accuracy of the lithography technique can be improved and an accurate color filter processing can be achieved.
Reference 1: Japanese Laid-Open Publication No. 2005-274967
Reference 2: Japanese Laid-Open Publication No. 2005-202252
Reference 3: Japanese Laid-Open Publication No. 2005-123225
Reference 4: Japanese Laid-Open Publication No. 2003-215321